In the related art, a centrifuge is provided with a chiller in which a compressor that operates using a commercial power supply is mounted. The centrifuge is configured such that when centrifugally separating a sample to be separated accommodated by the rotor through rotating at high speed, the inside of the rotor chamber is cooled through driving a chiller, and controls the temperature of the sample to be a desired target temperature, in order to prevent the temperature of the sample from increasing due to frictional heat between the air in the rotor chamber and the rotor.
Specifically, the temperature in the rotor chamber is sensed using a temperature sensor, and the chiller is controlled to be turned on or off. The temperature in the rotor chamber is controlled to be close to the desired target temperature while causing the temperature in the rotor chamber to pulsate by repeating overshooting and undershooting. At this time, in order to compensate for a temperature control error, a temperature correction value is used, which is the difference between the target temperature obtained in advance through experiment and the temperature of the sample, thereby aiming at a high accuracy of the control temperature.
Some of the above described chillers are configured such that a driving voltage thereof is different according to whether the power supply frequency is 50 Hz or 60 Hz. When adopting such a chiller, it is necessary to change the driving voltage which is supplied to the chiller according to the difference in the power supply frequency. For example, when it is a chiller which operates with a driving voltage in the vicinity of AC 100 V, it is necessary to supply a driving voltage of AC 100 V in an environment where AC frequency is 50 Hz, and supply a driving voltage of AC 115 V in an environment where the AC frequency is 60 Hz.
In recent years, there is more and more demand for the centrifuge to meet the overseas standard. Many of chillers which meet such overseas standards of China, North America, or the like, are not ones which operate with the same voltage regardless of the power supply frequency (50 Hz or 60 Hz), and the operating voltages thereof differ according to the power supply frequency. For this reason, a centrifuge manufacturer has performed the task of switching the voltage according to the destination country or region, specifically, the task of switching the transformer tap connection, or the like.
In addition, regarding the power supply frequency, there are countries in which 50 Hz and 60 Hz are used together, like Japan, there are also cases where it is not possible to automatically treat the switching for each country. In this case, the connection switching operation is to be performed locally by a local installation worker according to the power supply frequency of the location where the centrifuge is installed. Such work takes time, and may have operation error or the like. In addition, there is a problem in that a local installation worker may forget the task of switching the transformer tap connection.
As an example of electrical devices for which drive ability is different according to the difference in the power supply frequency, there is a cooling fan which is driven with an AC power supply. Since the cooling fan which is driven with AC power supply has a different number of revolutions according to whether the power supply frequency is 50 Hz or 60 Hz, the air amount and fan noise thereof are different. For this reason, in Japanese Patent No. 3291856, in order to secure the necessary air amount, or to reduce the fan noise, the power supply frequency is separated so as to control the voltage to be applied to the cooling fan, however, there is no mention of changing the driving voltage of the chiller in the centrifuge.